Frequency of HCMV reactivation in primitive hematopoietic subpopulations
. | Frequency of infectious centers* . | . | . | . | . | . | . | . | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| . | Lysate control† . | . | . | Reactivation . | . | . | . | . | |||||
| Population phenotype . | Replicates . | Average . | SD‡ . | Replicates . | Average . | SD‡ . | Fold increase§ . | P∥ . | |||||
| CD34+ | |||||||||||||
| 2.1 × 10-5 | 1.9 × 10-5 | — | 1.1 × 10-4 | 1.3 × 10-4 | — | 6.8 | — | ||||||
| 1.6 × 10-5 | 1.4 × 10-4 | ||||||||||||
| CD34+/CD38- | |||||||||||||
| 2.4 × 10-5 | 1.0 × 10-4 | ||||||||||||
| ≤ 1.0 × 10-5¶ | 2.3 × 10-5 | — | 1.1 × 10-4 | 1.2 × 10-4 | 2.1 × 10-5 | 5.2 | .002 | ||||||
| 3.4 × 10-5 | 1.4 × 10-4 | ||||||||||||
| CD34+/CD38+ | |||||||||||||
| 1.0 × 10-5 | ≤ 1.0 × 10-5¶ | ||||||||||||
| ≤ 1.0 × 10-5¶ | 1.0 × 10-5 | — | ≤ 1.0 × 10-5¶ | 1.0 × 10-5 | — | 1.0 | — | ||||||
| ≤ 1.0 × 10-5¶ | ≤ 1.0 × 10-5¶ | ||||||||||||
| CD34+/c-kit+ | |||||||||||||
| ≤ 1.0 × 10-5¶ | 1.0 × 10-5 | ||||||||||||
| ≤ 1.0 × 10-5¶ | 1.0 × 1.0-5 | — | ≤ 1.0 × 10-5¶ | 1.0 × 10-5 | — | 1.0 | — | ||||||
| ≤ 1.0 × 10-5¶ | 1.0 × 10-5 | ||||||||||||
| CD34+/c-kit- | |||||||||||||
| 1.2 × 10-5 | 2.6 × 10-5 | ||||||||||||
| 1.0 × 10-5 | 1.1 × 10-5 | 1.2 × 10-6 | 1.0 × 10-5 | 1.6 × 10-5 | 8.7 × 10-6 | 1.6 | .338 | ||||||
| 1.0 × 10-5 | 1.2 × 10-5 | ||||||||||||
| CD34+/CD38-/lin-/Thy-1+ | |||||||||||||
| 1.7 × 10-4 | — | — | 3.4 × 10-4 | — | — | 2.0 | — | ||||||
. | Frequency of infectious centers* . | . | . | . | . | . | . | . | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| . | Lysate control† . | . | . | Reactivation . | . | . | . | . | |||||
| Population phenotype . | Replicates . | Average . | SD‡ . | Replicates . | Average . | SD‡ . | Fold increase§ . | P∥ . | |||||
| CD34+ | |||||||||||||
| 2.1 × 10-5 | 1.9 × 10-5 | — | 1.1 × 10-4 | 1.3 × 10-4 | — | 6.8 | — | ||||||
| 1.6 × 10-5 | 1.4 × 10-4 | ||||||||||||
| CD34+/CD38- | |||||||||||||
| 2.4 × 10-5 | 1.0 × 10-4 | ||||||||||||
| ≤ 1.0 × 10-5¶ | 2.3 × 10-5 | — | 1.1 × 10-4 | 1.2 × 10-4 | 2.1 × 10-5 | 5.2 | .002 | ||||||
| 3.4 × 10-5 | 1.4 × 10-4 | ||||||||||||
| CD34+/CD38+ | |||||||||||||
| 1.0 × 10-5 | ≤ 1.0 × 10-5¶ | ||||||||||||
| ≤ 1.0 × 10-5¶ | 1.0 × 10-5 | — | ≤ 1.0 × 10-5¶ | 1.0 × 10-5 | — | 1.0 | — | ||||||
| ≤ 1.0 × 10-5¶ | ≤ 1.0 × 10-5¶ | ||||||||||||
| CD34+/c-kit+ | |||||||||||||
| ≤ 1.0 × 10-5¶ | 1.0 × 10-5 | ||||||||||||
| ≤ 1.0 × 10-5¶ | 1.0 × 1.0-5 | — | ≤ 1.0 × 10-5¶ | 1.0 × 10-5 | — | 1.0 | — | ||||||
| ≤ 1.0 × 10-5¶ | 1.0 × 10-5 | ||||||||||||
| CD34+/c-kit- | |||||||||||||
| 1.2 × 10-5 | 2.6 × 10-5 | ||||||||||||
| 1.0 × 10-5 | 1.1 × 10-5 | 1.2 × 10-6 | 1.0 × 10-5 | 1.6 × 10-5 | 8.7 × 10-6 | 1.6 | .338 | ||||||
| 1.0 × 10-5 | 1.2 × 10-5 | ||||||||||||
| CD34+/CD38-/lin-/Thy-1+ | |||||||||||||
| 1.7 × 10-4 | — | — | 3.4 × 10-4 | — | — | 2.0 | — | ||||||
— indicates not applicable.
Frequency of infectious centers is calculated by using a modified TCID50 assay based on a logistic model to allow precise extrapolation of the frequency of infectious center formation for experiments in which at least 2 wells were positive. The frequency is expressed as 1 divided by the number of cells required to yield 1 infectious center following reactivation as described in “Materials and methods.” In the event only 1 well was positive, the frequency was estimated to be 1 in 96 000 cells or 1.0 × 10-5.
A parallel series of limiting dilutions were plated following cell lysis to distinguish virus formed prior to reactivation from that formed following reactivation.
Standard deviations were calculated when at least 3 replicates yielded a reactivation frequency. SDs were not calculated for experiments in which the frequencies were estimated because of no wells scoring positively.
Fold increase in the frequency of reactivation compared with the lysate control.
By using the Student ttest, the probability (P value) that differences between the 2 averages were significant (P < .05) was calculated for experiments with 3 replicates.
When no wells were positive for reactivation, it was assumed that the frequency of infectious centers would be 1 or less in 25 wells or less than 1 in 96 000 cells. In this case, a value of ≤ 1.0 × 10-5 (1 in 96 000 cells) was used to estimate the upper limit of reactivation.